Yes Stefan, I mean exactly that. The special effects were all implemented on the YM6 format. The Sid-Voice effect was named liked that simply because it was sounding like a C64. My favourite effect though is the Sync-Buzzer! Tao took YMing to another level with this effect. Tao also used the Digi Drum and SID effects but it was the Sync-Buzzer that made him so popular. Any ST scener used to speak about SIDs when writing down music using the SID-Voice. If I remember well, I probably wrote a couple of tunes using SID-Voice. Still, chip music but with excellent quality.
As for your last example, there are some examples of pure digit tracks that sound much better than that. I need to look to my extended collection of YMs to find a few of them...
to try out (you need STSound
to play it since it is in original YM format)